1. Field of the Invention
The present invention relates to a portable electronic device. More particularly, the present invention relates to a portable electronic device having a touch panel.
2. Description of Related Art
With quick development of technology, potable electronic devices, such as personal digital assistant (PDA) mobile phones, have gradually become indispensable electronic products in people's daily life. Generally, a present PDA mobile phone has a touch panel, so that a user can directly operate the PDA mobile phone via a stylus or fingers. However, since the touch panel of the PDA mobile phone is generally a press touch panel formed by stacking a display, for example, a thin-film transistor liquid crystal display (TFT-LCD), and a touch panel, the touch panel fabricated based on such method has disadvantages of low display luminance and increasing of a thickness of the display.
Therefore, as to a portable electronic device requiring design features of lightness, slimness, shortness and smallness, a conventional method for fabricating the touch panel may lead to increasing of a whole thickness of the PDA mobile phone, and accordingly competitiveness of such PDA mobile phones is decreased. To effectively solve the disadvantages of the conventional touch panels, a light sensitive display disclosed by Boer et al. in U.S. Pat. No. 6,995,743 is provided, in which by integrating the touch panel with the display, and by sensing a shadow on the touch panel caused by operation of the stylus or finger, a position touched by the user on the touch panel is determined.
However, since the light sensitive display provided by Boer et al. has to utilize a charge readout amplifier to charge pixels irradiated with light, a signal on a readout line thereof is liable to be influenced, and accordingly a signal to noise ratio (S/N ratio) of the signal on the readout line is decreased, so that the light sensitive display provided by Boer et al. may misjudge or even cannot judge the position touched by the user on the touch panel.